Pentax shake reduction revisited (test)

Class A · 07-21-2010, 06:53 PM - **1 Like**

For anyone who has been watching the space: Falk published a white paper on shutter-induced blur. Highly interesting read(!) and of course highly related to this thread.

EDIT: A new, corresponding thread has been created on the matter.

Last edited by Class A; 07-21-2010 at 08:10 PM.

kittykat46 · 07-21-2010, 09:10 PM

Very good job you have done with this.

The U-shaped performance of the SR was something I had a gut feel after using the K-7 for just over a year, but you have worked it out with data.
SR is very helpful at really low shutter speeds - relative to the focal length, becoming less effective as the shutter speed increases. Eventually SR doesn't help at all, but at that high shutter speed, camera shake is not an issue.

Does the 1/100 sec dip in functionality related in any way to the shutter vibration effect you measured in the other thread ?

falconeye · 07-22-2010, 02:36 AM

Originally posted by kittykat46

Does the 1/100 sec dip in functionality related in any way to the shutter vibration effect you measured in the other thread ?

Yes. Actually, there was no dip in functionality. Only the extra blur from the shutter masking the working of the SR.

If you use really long focal lengths (e.g., 300mm), the free hand shake is always large enough to be the dominant source of blur (even at 1/100s) and then you see SR works the same at all speeds. Except that it can't do anything against shutter-induced blur.

So, we'll have to update the SR guide now.

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07-21-2010, 06:53 PM - 1 Like	#31
Class A Pentaxian Join Date: Aug 2008 Location: Wellington, New Zealand Posts: 11,251	For anyone who has been watching the space: Falk published a white paper on shutter-induced blur. Highly interesting read(!) and of course highly related to this thread. EDIT: A new, corresponding thread has been created on the matter. Last edited by Class A; 07-21-2010 at 08:10 PM.

07-21-2010, 09:10 PM	#32
kittykat46 Veteran Member Join Date: Dec 2007 Posts: 923	Very good job you have done with this. The U-shaped performance of the SR was something I had a gut feel after using the K-7 for just over a year, but you have worked it out with data. SR is very helpful at really low shutter speeds - relative to the focal length, becoming less effective as the shutter speed increases. Eventually SR doesn't help at all, but at that high shutter speed, camera shake is not an issue. Does the 1/100 sec dip in functionality related in any way to the shutter vibration effect you measured in the other thread ?

07-22-2010, 02:36 AM	#33
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871 Original Poster	Originally posted by kittykat46 Does the 1/100 sec dip in functionality related in any way to the shutter vibration effect you measured in the other thread ? Yes. Actually, there was no dip in functionality. Only the extra blur from the shutter masking the working of the SR. If you use really long focal lengths (e.g., 300mm), the free hand shake is always large enough to be the dominant source of blur (even at 1/100s) and then you see SR works the same at all speeds. Except that it can't do anything against shutter-induced blur. So, we'll have to update the SR guide now.